Within the field of computing, many scenarios involve an item set comprising a set of items managed by an item server, such as a mailbox comprising a set of mail messages stored by a mail server, a file system comprising a set of files stored by a file server, and a database comprising a set of records stored by a database server. Within such item sets, an action requested by a user or process may be applied that may take a considerable amount of time and/or processing power to complete, particularly if the action is complex and/or the item set is large. However, the item server may be configured to service many processes and/or users, and it may be undesirable to apply the entire operation to the item set as an uninterruptible transaction, because this application may deprive the other processes and/or users of computing resources (e.g., the item set may have to be exclusively locked in order to perform the action, or the bandwidth, memory, or computational capacity of the server may be exhausted while performing the operation). Therefore, many item servers may execute the action under a constraint, such as a maximum amount of time, computational capacity, memory, and/or bandwidth that may be consumed by the action. Actions that exceed this constraint may be suspended or terminated by the item server; or, if the action appears likely to exceed the constraint, the item server may simply refuse to perform the action.